Effect of Surface Molecular Aggregation State and Surface Molecular Motion on Wetting Behavior of Water on Poly(fluoroalkyl methacrylate) Thin Films

Abstract

The effect of surface molecular motion on the wetting behavior of water on the thin film surfaces of poly(fluoroalkyl methacrylate)s with various fluoroalkyl (R f ) groups [PFMA-C y ; y: fluoromethylene number in R f groups, y = 1, 2, 4, 6, and 8] was characterized. The receding contact angle of PFMA-C y with short R f groups (y = 1, 2, 4, and 6) was larger than that of poly(fluoroalkyl acrylate) with short R f groups [PFA-C y , y e 6]. This stable hydrophobicity observed for PFMA-C y is due to the restriction of thermal molecular motion by the R-methyl group. Wide-angle X-ray diffraction (WAXD) and grazing incidence WAXD measurements revealed that the R f groups [PFMA-C y , y e 6] were not crystallized. PFMA-C 8 showed high advancing and receding contact angles due to the crystallization of fluoroalkyl groups at the surface region. The hydrophobicity of PFMA-C 8 was improved after annealing due to the ordering of fluoroalkyl groups.

Surface orientation of hydrophilic groups in sulfonated poly(ether ether ketone) membranes

“…9b), until a thick viscous polymer solution evolved into a primary solid membrane, the hydrophilic glass substrate gave rise to higher sulfur atom concentration at the bottom surface of a membrane than at its corresponding top surface. After the membrane was peeled from the glass plate, the membrane was left into a vacuum oven for further drying process in which temperature was increased 32 gradually up to 120 o C and kept constant for 24 h. During this process, both sides of the membrane were towards vacuum (Fig. 9c), which is a zero surface tension medium [30].…”

Effect of α-substituents on molecular motion and wetting behaviors of poly(fluoroalkyl acrylate) thin films with short fluoroalkyl side chains

“…The previous study suggested that the mobility of the molecular chain affects the wetting properties [15].…”

Structural analysis and surface wettability of a novel alternated vinylidene cyanide with fluorinated vinyl ether copolymer

“…Therefore, the increase in g s can be attributed to the strong dipole-dipole interactions between the CN groups and the lower-ordered smectic structure and lower orientation of the R f group in the poly(VCN-alt-FAVE8) copolymer compared with the S B phase of poly(FA-C 8 ). 13,25,26 The dynamic contact angles of both poly(VCN-alt-FAVE8) and poly(FA-C 8 ) thin-films (the latter being regarded as the reference) are summarized in Table 3 and shown in Figure 5. A sliding water droplet on the poly(VCN-alt-FAVE8) copolymer thin-film formed an asymmetric shape with a high y A and low y R .…”

“…It is generally claimed that fluorinated side groups such as C 8 F 17 have the optimal surface properties/price ratio, although some compounds that contain C 8 F 17 , for example, perfluorooctanoic acid, perfluorooctane sulfonic acid and their derivatives, are now criticized as environmental and health risks. 6 Of the numerous homopolymers based on methacrylates, [7][8][9][10][11][12][13] vinyl ethers [14][15][16][17] and styrenes [18][19][20][21] bearing such a group, polyacrylates with a perfluorooctyl ethyl side chain, poly(FA-C 8 ), possess excellent surface properties because the side chains form a highly ordered lamellar phase with the C 8 F 17 chains aligned perpendicular to the surface. [22][23][24][25][26] However, their thermal stabilities are not high.…”